1. Field of the Invention
The present invention relates to a signal processing method and a signal processing apparatus. More particularly, the present invention is designed to read a candidate signal and a comparison signal for a predetermined time from the signals of content recorded in recording means and to detect a signal with identical content by comparing the candidate signal with the comparison signal. Furthermore, when the signal with identical content is detected, this signal is stored, and the signal which is the same as the stored signal is deleted from the recording means. In the deletion of this signal, by deleting the signal, the recording means is efficiently used in such a manner that the deleted signal can be determined.
2. Description of the Related Art
In recent years, as the capacity of recording means, for example, optical disks and hard disks capable of performing a random access operation, becomes larger, not only computer data, but also various content signals, for example, audio data and moving image data, have been recorded. Furthermore, in removable and portable recording media, similarly to conventional audio cassette tapes and video cassette tapes, signals of broadcast programs, etc., have been recorded in such a manner that these signals can be stored as signals of video and audio content. In addition, when a recording medium is provided in a fixed manner within a signal processing apparatus, a broadcast program which cannot be viewed is temporarily recorded by a timer reservation operation. Also, a recording operation is started from a position at which a broadcast program cannot be viewed in real time, and when a situation capable of being viewed is reached, not only the recording operation, but also a playback operation of the broadcast program recorded on the recording medium is performed at the same time, so that an operation for allowing a desired broadcast program to be continuously viewed is performed. Furthermore, when a recording and a playback of a program are performed simultaneously, the program playback position is also brought closer to the real-time broadcast program being recorded by speeding up the playback speed or by skipping commercial portions.
In recording media, such as video cassette tapes, which are incapable of performing a random access operation, signals of content, such as broadcast programs, are recorded in sequence, and when only a desired program portion is to be played back, a tape fast-forwarding operation and a tape rewinding operation for skipping a portion which is not viewed must be performed. In this manner, since a tape fast-forwarding operation and a tape rewinding operation must be performed each time for a playback in a portion which is not viewed, operations become complicated. For this reason, for example, when a television broadcast program is to be recorded/played back, it is performed such that a sound mode switching position is detected and a commercial portion is skipped. In this process of skipping a commercial portion, it is performed such that that a commercial portion of a stereo mode, which is inserted into a program in which sound is in a monaural mode, or a commercial portion of a stereo mode, which is inserted into a program of a bilingual sound mode, is determined from the switching position of the sound mode, and this determined commercial portion is automatically skipped. However, in a system which determines such a sound mode switching position, a commercial portion of a stereo mode, inserted into a program of a stereo mode, cannot be detected.
Furthermore, there are cases in which signals, of which contents are the same, are recorded in a duplicated manner on recording media. For example, when a desired broadcast program is to be recorded on a recording medium, there are cases in which a commercial of the same content is repeatedly broadcast in the middle of the program. In such a case, commercial signals of the same content will be recorded in a duplicated manner. Furthermore, when a serialized drama is to be recorded collectively on one recording medium, the signals of the opening portion and the ending portion, in which the content is the same, are recorded in a duplicated manner, and thus, the recording medium will not be used efficiently.